Method for joining the ends of strip stock



A ril 15, 1969 F. J. MOLTCHAN METHOD FOR JOINING THE ENDS OF STRIP STOCK Filed Oct. 31, 1963 Sheet of 5 mvsmon.

FLOYD J. MOLTCHAN his ATTORNEY.

April 15, 1969 F. J. MOLTCHAN METHOD FOR JOINING THE ENDS OF STRIP STOCK Sheet 2 of5 Filed OOt. 51, 1963 Fig.2.

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FLOYD J. MOLTCHAN his ATTORNEY.

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r FLOYD J. MOLTCHAN 64 glsJFi gaA-l- %M%ZATTORNEY April 15, 1969 F. J. MOLTCHAN METHOD FOR JOINING THE ENDS OF STRIP STOCK Sheet 4 off:

Filed Oct. 31, 1963 INVENTOR.

FLOYD J. MOLTCHAN 8; S37

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his ATTORNEY Sheet of 5 INVENTOR.

FLOYD J. MOLTCHAN B his ATTORNEY F. J. MOLTCHAN METHOD FOR JOINING THE ENDS OF STRIP STOCK ZVZ/ April 15, 1969 Filed Oct. 31, 1963 Fig.8E-I.

United States Patent US. Cl. 29-509 5 Claims ABSTRACT OF THE DISCLOSURE Described is a method for joining the trailing and leading ends of strip stock taken from coils wherein the trailing and leading ends of the strip stock are initially overlapped to form superposed portions, an opening is pierced in the superposed portions to form a pair of spaced-apart, generally rectangular partly curled tongues, and these tongues are further reversely bent and flattened in opposite directions whereby both of the tongues extend transversely of the length of the strip stock. Preferably, a plurality of such pierced openings are provided across the width of the strip stock together with sheared depressions which engage the overlapped ends of the strip stock.

Although not limited thereto, the present fastening method is particularly adapted for use in joining the ends of flat strip material taken from coils. That is, the trailing end of one coil is secured to the leading end of the next to be used coil of flat strip material. The flat strip material may be used in processing lines such as painting, coating, galvanizing, plating, annealing and the like.

' Heretofore, the trailing and leading ends of strip stock have been joined by several well known methods, as for example, butt-welding, spot-welding, stapling, riveting and the like. In butt-welding, the ends of the strip stock must be cut square. Thereafter, the ends are butted and welded. In spot-welding, the ends of the strip stock are overlapped whereupon the ends are spot-welded at a plurality of places. In stapling, the ends of the strip stock are first overlapped whereupon a plurality of staples are driven through the overlapped ends. In riveting, the ends are first overlapped whereupon a plurality of holes are drilled through both sheets. Thereafter, the rivets are inserted into the holes and driven in place to secure the ends together. As should be obvious, these methods are both relatively expensive and time consuming. Furthermore, these methods require the use of extrinsic fastening elements which merely add to the cost of the joining operation.

According to the present invention, a stitcher die is provided comprising an upper and a lower die shoe and which is slideably mounted in a conventional punch press. The upper die shoe carries a plurality of punch elements having a V-shaped sheet-piercing end. As the upper die shoe descends, the punch elements pierce and shear the overlapped ends of the strip stock to provide a row of openings extending transversely of the length of the strip stock. Each of the punch elements pierces and shears the overlapped ends in such a manner whereby a pair of spaced-apart partly curled tongues is formed. The partial curling of the tongues is produced by the shearing action of the V-punches. As the upper die shoe continues to descend, the partly curled tongues engage a forming block whereby they are further reversely bent and flattened in opposite directions to lock the overlapped ends tightly together. Hence, the tongues so formed may be aptly named locking tongues.

A single row of locking tongues may be provided for joining the ends of relatively heavy gage sheet metal, i.e., a gage range from about 11 gage to 18 gage. For joining 3,438,119 Patented Apr. 15, 1969 the ends of intermediate gage sheet metal, i.e., a gage range from about 18 to 23 gage, two rows of locking tongues may be provided which rows are spaced apart and substantially parallel.

For joining the ends of relatively light gage sheet metal, i.e., a gage range from about 23 to gage, the upper die shoe may be provided with two spaced-apart, substantially parallel rows of the first-mentioned punch elements and a second row of shearing elements disposed between the parallel rows of punch elements. The shearing elements are adapted to engage the overlapped ends of the strip stock after the locking tongues have been re versely bent. The shearing elements serve to shear the overlapped ends along line segments which are aligned transversely with respect to the length of the strip stock. The sheared line segments preferably are disposed centrally between adjacent ones of the tongues of the two rows of openings. In shearing the overlapped ends along said line segments, pairs of opposed sheared edges are formed. Those sheared edges which are leading with respect to the travel of the strip stock are depressed downwardly whereby the upper ones of the depressed sheared edges are displaced into engagement with those sheared edges which are trailing with respect to the travel of the strip stock. The flattened tongues maintain the sheared edges in engagement. The elements formed by the shearing punches may be aptly named depressions.

The combined action of the rows of locking tongues and the depressions thus formed creates a strong connection between the overlapped ends which is not adversely effected by the tension forces applied to the strip material as the strip stock proceeds through the processing line. There is no tendency, for example, for the ends of the strip stock to curl upward and downward when a tension force is applied. The curling of the end is eliminated because portions of the sheared edges of the upper sheet are in direct shear and compression at spaced points with the lower sheet.

Accordingly, the primary objects of the present invention include:

To provide a method of joining the ends of strip stock without the use of extrinsic fastening elements;

To provide a method for joining the ends of strip stock by means of piercing the overlapped ends thereof whereby integral portions of the strip stock are employed to secure the ends together;

To provide a method for joining the ends of strip stock whereby the tendency for the ends to curl upward and downward under a tension force is eliminated; and

To provide a method for joining the ends of strip stock in which the joint may be rapidly and relatively in expensively accomplished.

These and other objects and advantages of the present invention will become apparent from the following detailed description by reference to the accompanying drawings, in which:

FIGURE 1 is a front elevation view of the present stitcher die;

FIG. 2 is a cr0ss-sectional view, taken along the line II-ll of FIG. 1, illustrating the present stitcher die in an open condition;

FIG. 3 is a cross-sectional view, taken substantially along the line III-III of FIG. 2, illustrating the present stitcher die in a closed condition;

FIG. 4 is a fragmentary plan view of the overlapped ends of the strip stock which have been joined in the manner contemplated by the present invention;

FIG. 5 is a cross-sectional view, taken along the line V-V of FIG. 4;

FIG. 6 is a cross-sectional view, taken along the line VIVI of FIG. 4, illustrating a pair of locking tongues;

FIG. 7 is a cross-sectional view, taken along the line 3 VII-VII of FIG. 4, illustrating a pair of depressions; and FIGS. 8A-l to 8E-l are views schematically illustrating the method of forming the locking tongues of the present invention and FtIGS. 8A-2 to 8E2 are views schematically illustrating the method of forming the depressions of the present invention.

Present stitcher die Referring now to FIGS. 1, 2 and 3, the present stitcher die, generally indicated by the numeral 10 is shown comprising an upper die shoe 12 and a lower die shoe 14. The upper die shoe 12 includes bushings 16 which are slideable on and guided by post members 18 rigidly mounted on the lower die shoe 14. A press bed frame 20 includes a support plate 22 upon which rests the lower die shoe 14. The lower die shoe 14 is mounted for reciprocal sliding movement over the support plate 22 and is guided during its movement by means of guide bars 24 (see FIG. 2) secured to the support plate 22.

The upper die shoe 12 also is mounted for reciprocal sliding movement beneath a press ram member 26 and is guided during its movement, by means of additional guide bars 24 (see FIG. 2) secured to the press ram member 26. A drive means (not shown) is connected to the press ram member 26 and serves to lower and raise the upper die shoe 12 when joining the ends of strip stock.

Mounted on the press bed frame 20, adjacent to one side of the stitcher die 10, is a cylinder 28 having a piston shaft 30 which extends therefrom and is secured to the lower die shoe 14. When pressurized, the cylinder 28 will move the stitcher die 10 to the left, as viewed in FIG. 1, through a predetermined distance. By reversing the direction of the pressurizing medium within the cylinder 28, the stitcher die 10 will be moved to the right, as viewed in FIG. 1, through the same predetermined distance to return it to the position shown in FIG. 1. The purpose of moving the stitcher die 10 back-and-forth will become apparent later in the specification.

To the upper die shoe 12 is secured a plurality of carrier blocks 32. Secured to the carrier blocks 32 are punch elements 34 and shearing elements 36. Each carrier block 32 also supports a stripper plate 38 which is guided for vertical travel on shouldered screws 40 which are secured to the stripper plate 38 and freely slideable in bores 41 provided in the carrier blocks 32. Each of the stripper plates 38 is biased in the downward direction, by means of spring members 42, as illustrated in FIG. 1.

Directly below each of the carrier blocks 32 is a hardened die steel plate or support block 44 rigidly mounted on a sub-die plate 46 forming part of the lower die shoe 14. The die steel plate 44 is provided with a plurality of rectangular openings 47 which are adapted to receive forming blocks 48 rigidly secured to the lower die shoe 14. The forming blocks 48 have openings 49 adapted to receive the punch elements 34. The die steel plate 44 also is provided with a plurality of openings 51 which are adapted to receive the shearing elements 36.

In front and in back of each die steel plate 44 are stripper pads 52 which project above the upper surface of the die steel plates 44 as shown in FIG. 2. Each stripper pad 52 includes at least two guide shafts 54 extending into the die plate 46. A spring member 56 surrounds each of the guide shafts 54 and is adapted to bias the stripper pads 52 in the elevated position shown in FIG. 2.

The die plate 46 is biased in an upward direction by means of a series of spring members '58 (see FIG. 3) which are disposed between the die plate 46 and the lower die shoe 14. A plurality of guide members 62 (see FIG. 2) are employed to guide the vertical movement of the die plate 46.

The present stitcher die 10 has a definite sequence of operation which is controlled by means of cooperating cam means now to be described. As can be seen by comparing FIGS. 2 and 3, a master cam assembly 64 is provided which comprises a pair of primary cam means 66 (one at each end) and secondary cam means 68 all of which extend transversely of the die plate 46 and are secured at their ends to bar members 70. The master cam assembly 64 has a ladder-like configuration and rests on the upper surface of the lower die shoe 14. The master cam assembly 64 is biased to the left, as viewed in FIGS. 1 and 3, by means of spring members 72 (only one visible) which extend between one of the primary cam means 66 and a block 7-4 which is secured to the lower die shoe 14. The block 74 has retaining rods 76 extending therefrom on which the spring members 72 are mounted. The master cam assembly 6-4, thus, is adapted for horizontal reciprocal movement and is guided during this movement by means of a pair of guide members 78 each of which is engaged in guiding relation with one of the bar members Referring now to FIGS. 1 and 3, the upper die shoe 12 has a pair of primary cam actuators 80 depending therefrom and which are aligned with the primary cam means 66 (see FIG. 1). Each of the primary cam actuators 80 includes a cam surface 82 which is adapted to engage a cam surface 84 provided on each of the primary cam means 66. The die plate 46 of the lower die shoe 14 includes a plurality of secondary cam actuators 86 each of which includes a cam surface 88 adapted to engage the cam surface 90 of the secondary cam means 68. As can be seen in FIG. 1, the secondary cam actuators 86 initially rest on top of the secondary cam means 68. Hence, as the master cam assembly 64 is moved to the right, as viewed in FIG. 1, the secondary cam means 68 also will move to the right and slide on the secondary cam actuators 86 until the cam surfaces 88 and 90 are engaged.

Referring to FIG. 2, a trailing end 92 of the flat strip stock being processed is shown disposed beneath a leading end 94 of a coil of flat strip stock shown in dotted outline at 96 which is being prepared for processing. The overlapping ends 92, 94 form superposed portions 98 which are positioned between the upper and lower die shoes 12, 14 of the stitcher die 10. The direction of travel of the strip stock is indicated by the arrow 100. As shown Resulting joint Illustrated in FIG. 4 on an enlarged scale, is a fragment of the superposed portions 98 which have been joined in the manner contemplated by the present invention. The stitcher die 10, as illustrated in FIGS. 1, 2 and 3, would provide three substantially parallel rows of locking elements 102 and two substantially parallel rows of depressions 104. The rows of locking elements 102 and the depressions 104 extend transversely of the length of the strip stock.

One operation of the stitcher die will provide a series of the locking elements 102 and the depressions 104 as shown in solid lines in FIG. 4. By pressurizing the cylinder 28 (see FIG. 1), the stitcher die 10 will be moved to the left, as viewed in FIG. 1, through the predetermined direction indicated at 106 in FIG. 4. A second operation of the stitcher die 10 will provide a second series of the locking elements 102 and the depressions 104 along the dotted lines shown in FIG. 4. Since the stitcher die 10 is operated twice for each joint in heavy gage material the force requirements of the press are halved.

Referring now to FIGS. 4, 5 and 6, the end of each punch element 34 is V-shaped (see FIG. 3). Hence, each punch element 34 pierces an opening 110 by cutting the superposed portions 98 along an H-shaped out line shown in dotted lines at 108 whereby a pair of partly curled looking tongues 112 are formed which are' subsequently further reversely bent as shown in FIG. 6. As can be seen in FIG. 6, the locking tongues 112 comprise portions 94A of the leading end 94 and portions 92A of the trailing end 92. The portions 94A extend through the opening 110 in the trailing end 92 whereupon both of the portions 92A and 94A are reversely bent.

Each shearing element 36 has a transverse substantially conical end portion 113 (compare FIGS. 2 and 3) which is adapted to shear the superposed portions along line segments shown in dotted lines at 114 (in FIG. 4) to form opposed sheared edges 116 and 118. The shearing elements 36 simultaneously depress the superposed portions 98 in the region of the sheared edges 116 whereby the upper one of the sheared edges 116 is displaced into engagement with the lower one of the sheared edges 118. It should be noted that the sheared edges 116 are leading with respect to the travel of the strip stock as indicated at 100. Hence, when the trailing end 92 is pulled whereby it is placed in tension, the sheared edges 118 thereof will engage the sheared edges 116 of the leading end 94.

Operation of stitcher die The sequence of operation of the stitcher die is schematically illustrated in FIGS. 8A7 through 8E-2. FIGS. 8A-l to 8E1 illustrate the formation of the locking tongues 112 while FIGS. 8A2 to 8E2 illustrate the for mation of the depressions 104. It should be understood, however, the FIGS. 8A-1 and 8A-2 illustrate the positions of the various components at one step in the sequence. Similarly, FIGS. 8B-1 and 8B-2; FIGS. 8C-1 and 8C2; and so forth illustrate the positions of the various components at other steps in the sequence.

Referring to FIGS. SA-l and 8A-2, the upper die shoe 12 first is lowered whereby the superposed portions 98 are clamped between the stripper plate 38 and the upper surface of the die steel plate 44. Further, the first of the punch elements 34 is engaged with the upper one of the superposed portions 98.

As the upper die shoe 12 descends, as can be' seen in FIGS. 8B-1 and 8B-2, the punch elements 34 pierce the superposed portions 98 to form the locking tongues 112. Because of the method of piercing, each of the locking tongues 112 is given an outward curl. The rectangular apertures 47 in the die steel plate 44 provide the necessary space into which the locking tongues 112 extend. As can be seen in FIG. 8B-1, the primary cam actuator 80 has engaged the primary cam means 66 whereby continued lowering of the upper die shoe 12 will result in the movement of the master cam assembly 64 to the right as indicated by the arrows. It is important to note, that although the master cam assembly 64 is moved to the right, the secondary cam means 68 supports the lower die shoe 14 and maintains it stationary during the formation of the tongues 112. This can be seen by comparing FIGS. 8B-l and 8Cl.

The upper die shoe 12 and the primary cam actuator 80 continue to descend until they reach the positions illustrated in FIGS. 8C1 and 8C-2. At this time, all of the locking tongues have been formed with the curl and all of the depressions 104 have been formed. At this point in the downward travel of the upper die shoe 12, the master cam assembly 64 has moved a suificient distance to the right whereby the cam surfaces 88 and 90 are about to be engaged so that the die steel plates 44 along with the die plate 46 will begin to descend. Up to this point, the die steel plates 44 and the die plate 46 have remained stationary by virtue of the secondary cam actuator 86 being engaged with the upper surface of the secondary cam means 68. Noted, however, that the forming blocks 48 remain stationary at all times.

Referring now to FIGS. 8D-l and 8D-2, the rightward movement of the master cam assembly 64 permits the simultaneous downward travel of the upper die shoe 12 and the die steel plates 44. As can be seen, the extreme lower ends of the locking tongues 112 will engage the upper surfaces of the forming blocks 48 whereby they are further reversely bent and flattened in the manner illustrated in FIG. 8 E-1. The initial partial curl given the locking tongues 112 during the piercing operation (FJGS. 8A-l to SC-l aids considerably in directing the tongues 112 away from the punch elements 34.

FIG. 8E illustrates the die shoe 12 at its lower limit of travel. At this time the upper die shoe 12 will be reversed in its travel and be elevated to that position shown in FIG. 1. While the die shoe 12 is being elevated, the stripper pads 52 (see FIGS. 13) will insure the disengagement of the depressions 104 and tongues 112 from the openings 51 and 47 respectively. The stripper plates 38 will insure the disengagement of the punch elements 34 and 36 from the openings in the superposed portions 98.

It is important to note that FIGS. 8A-1 to 8E-2 represent one downward stroke of the stitcher die 10. Hence, during one downward stroke of the stitcher die 10, the locking tongues 112 are formed, reversely bent and flattened and the depressions 104 are formed.

Although the invention has been illustrated in connection with a certain specific embodiment, it will be readily apparent to those skilled in the art that various changes in form and arrangement of parts may be made to suit requirements without departing from the spirit and scope of the invention.

I claim as my invention:

1. The method of joining the trailing and leading ends of strip stock taken from coils comprising the steps of: overlapping the trailing and leading ends of said strip stock to form superposed portions; piercing an opening in said superposed portions along an H-shaped out line with the crossbar of the H-shape being parallel to the length of said strip stock to form a pair of spaced-apart, generally rectangular partly curled tongues depending therefrom; and further reversely bending and flattening said tongues in opposite directions whereby both of said tongues extend transversely of the length of said strip stock.

2. The method of joining the ends of strip stock comprising the steps of: overlapping the ends of said strip stock to form superposed portions; piercing a pair of spaced-apart openings in said superposed portions to form a pair of spaced-apart partly curled tongues depending from each of said openings, said openings being aligned with the length of said strip stock; further reversely bending and flattening said togues in a direction transverse to the length of said strip stock; and shearing said superposed portions in the region between adjacent ones of said tongues along at least one line segment to form opposed sheared edges which are spaced from said openings and extend transversely of the length of said strip stock, while simultaneously depressing the sheared edges leading with respect to the direction of travel of said strip stock whereby the upper one of the depressed sheared edges is engaged with the lower one of the undepressed sheared edges.

3. The method of joining the ends of strip stock comprising the steps of: overlapping the ends of said strip stock to form superposed portions; piercing a pair of spaced-apart openings in said superposed portions to form pairs of spaced-apart curled and flattened tongues, one pair depending from each of said openings, said openings being aligned with the length of said strip stock, further reversely bending and flattening said tongues in a direction transverse to the length of said strip stock; and shearing said superposed portions in the region between adjacent ones of said tongues along two, spaced transverselyaligned line segments to form sheared edges which are spaced from said openings, while simultaneously depressing those sheared edges leading with respect to the travel of said strip stock whereby the upper one of said sheared edges is depressed into engagement with the lower ones of the sheared edges which are trailing with respect to the travel of said strip stock.

4. The method of joining the trailing and leading ends of strip stock taken from coils comprising the steps of: overlapping the ends of said strip stock to form superposed portions; piercing a plurality of transverselyaligned openings in said super-posed portions along H-shaped cut lines with the crossbar of the H-shape being parallel to the length of the strip stock to form pairs of spaced-apart curled and flattened tongues, one pair depending from each of said openings; and further reversely bending and flattening all of said pairs of tongues in a direction which is transverse to the length of said strip stock whereby said superposed portions are tightly locked together.

5. The method of joining the ends of strip stock comprising the steps of: overlapping the ends of said strip stock to form superposed portions; piercing first and second rows of transversely-aligned openings in said superposed portions to form pairs of curled and flattened tongues, one pair of tongues depending from each of said openings, said first and second rows extending transversely of the length of said strip stock; further reversely bending and flattening all of said tongues in a direction transverse to the length of said strip stock; and shearing said superposed portions along line segments in the region of adjacent ones of said reversely-bent and flattened tongues and spaced therefrom to form opposed sheared edges, while simultaneously depressing those sheared edges leading with respect to the travel of said strip stock whereby the upper ones of said sheared edges are depressed into engagement with the lower ones of the sheared edges which are trailing with respect to the travel of said strip stock.

References Cited UNITED STATES PATENTS CHARLIE T. MOON, Primary Examiner.

US. Cl. X.R. 29-211; 113--1 

